Choosing which diet you like best may not mean you'll lose more weight.

In fact, picking a weight-loss plan based on your food preferences might backfire and lead to less weight loss, new research suggests.

After comparing two groups, one in which dieters could choose one of two eating plans and one in which dieters were randomly assigned to one of the plans, the researchers found those who had a choice lost slightly less weight than those who had no choice.

"[The difference in weight loss] was not statistically significant," admitted study author Dr. William Yancy Jr., a research associate in the Center for Health Services Research in Primary Care at Duke University, in Durham, N.C. "The weight loss was similar between the two groups. It's just that the direction of effect was not even in the expected direction."

For the study, published in the June 16 issue of the Annals of Internal Medicine, 207 people were randomly assigned to one of the two groups.

The study lasted 48 weeks, during which both groups received group and telephone counseling.

Researchers theorized that by allowing some people to choose a diet that included foods they liked, they would stick with it and lose more weight than those who were assigned to their diets. They even allowed the choice group the option to switch diets after 12 weeks if they were unsatisfied with their initial decision. Very few took the researchers up on their offer.

After 48 weeks, the choice group lost an average of 12.6 pounds while the other group lost an average of 14.8 pounds.

Since the study did not show long-term success for maintaining weight loss, and the difference in weight loss between the two groups was not statistically significant, could choosing a diet plan based on food preferences be better in the long run?

"That is certainly a reasonable argument," Yancy said. "However, for those who are looking for ways to enhance the weight-loss effects of lifestyle modification, choosing a diet based on food preferences does not seem to do that."

He added that the best diet for some may be one where they have to try new foods.

"It may require people to attempt to incorporate new foods into their diets to be most successful," Yancy said. "The good news is that we know that our tastes can adapt to such new foods and begin to enjoy them more over time."

Christine Santori is program manager for the Center for Weight Management at North Shore-LIJ's Syosset Hospital in Syosset, N.Y.

"Incorporating one's food preferences and involving the patient in the meal planning will increase long-term compliance and sustained weight loss," said Santori, who was not involved in the research.

She did warn, though, that choosing a diet plan based on food preferences that may be high in calories could make it hard to control portion size and ultimately lead to less weight loss.

"In my opinion, it is best to select a meal plan based on one's metabolic profile and work to incorporate the individual food preferences with patient involvement," she said.

The researchers agreed, and added that future research should focus on matching dieters with the optimal diet by using their metabolic or genetic profiles.

"A metabolic profile could be any number of blood tests -- or other tests -- that reflect [what's going on in] the body," said Yancy. "These could include tests that are commonly done at [checkups with your health care provider], such as blood lipids, glucose or insulin [levels]."

He explained, for example, that preliminary research suggests that people with insulin resistance, low HDL (good) cholesterol or high triglycerides (blood fats) may benefit from a low-carbohydrate diet.

"As for genetic profiles," Yancy added, "we have learned of a number of gene variants that increase risk for obesity or diabetes. It could be that people with certain variants respond better to one diet versus another diet."